fesler



May 26, 1925 1,539,249

M. A. FESLER SAFETY DEVICE FOR OIL BURNERS Filed Se t. 2. 1924 2 Sheets-Sheet, 1

/ l EN OR A TTORNEY i A a I TL F May 26, 1925.

M. A. FESLER SAFETY DEVICE} FOR OIL BURNERS 2 Sheets-Shet 2 Filed Sept. 2 1924 I A I ATTORNEY PM: Ma tze, 1925;

U ED". STATES PAT E'NT OFFICE Infra A. rEsEEn, or s'rsmronn, conivncrrcuzr, ASSIGNOB T PETROLEUM HEAT &

V rownacomrm, or nos'ron, mnssacnusnrrsn conroaa'rron or DELAWARE.

sAEE'rY DEVICE son on, BURNERS,

, Application filed September 2, 1924. Serial No. 735,860.

To all whom I Be it known that;I, MILTON A FESLER, a

- citizen of the United States, residing at Stamford 'in the county of Fairfiel'd and State of o'nnecticua have invented an Improvement in Safety Devices for Oil Burners, of'which the following description, in connection with the accompanying drawin s, is a specification, like characters on tie drawings representing like parts.

The present inventionrelates more particularly to safety devices for electrically ignited oil burners, -but is not necessarily limited in its use to oil burners.

The use of oil as a fuel for furnaces is ac-. companied by more or less danger of fire, due to the fact that it is necessaryto furnish the oil burners with a continuous supply of fuel, and if through any cause the fuel is not consumed 'as it leaves the burner it will accumulate in on nearthe -furnace in a 'hi hly inflammable condition. o

Tarious means have been proposed heretofore for ignitin the fuel as it is deliveredto produce the ignition spark, inwhich case oil maybe discharged from the burner'without being consumed ,andaccumulate in -a dangerous condition. v p

It has-been attempted to provide means for automatically stopping the supply of fuel to a burner when the-ignitiohjspark plug fails to produce an electric this problempresents various. fiiculties and it is believed no satisfactory means to this end has been devised prior to the present invention. r i

.One of the diiiiculties' experienced ,in attempting to provide electrically .operatedmeans that will cut off the-'supply'of fuel when the sparklug fails toproduce a V spark, is due to t "e factthat the current s ark but (g 7 commonly supplied to a spark plug, altho of high voltage, is of such low amperage that trol de'vices. p

An important purpose of the present in- -it will not'operate the 'usual electrical'conivention, therefore, in its broad aspect, is toprovide means for utilizing the low amper age electric currentsuch as supplied to'spark plugs, to control the position of a controller. so that the controller will occupy one position as long as' the current is suppliedand will occupy a different position. when the current fails, I, A more specific purpose of. the invention is to rovidemeanscontrolled by the current 1 at crosses the spark gap of a spark plug'and which Willjoperate automatically to stop the supply of fuel to the burner if the spark plug .fails to produce the ignition Spark .fl

In carrying out the present invention ad'- vantage is taken of the fact that, altho the amount of electric energy required to produce a spark betweenthe terminals of a spark plug is small, it'is sufficient toheat the ends of these terminals to a high temperature, and this hi h temperature is uti,'

lized in accordance with the present invention to heat a piece of thermostatic metal so that as long as this. metal is heated it will hold a valve, switchor other element in onepo'si 'tion, and when the heat produced by the electric current fails it will move the valve, switch or other element toa different posii-o o The jresent invention may be givenfva-ri ous em odiments, and in one construction shown, air pressure is employed to feedvfuel to the burner, and'the thermostartlc metal that is heated by. a terminal-of a spark gap serves to operate a valve so-that when-the electric current failsthe valve is. automatically opened to relieve theair pressure to thereb stop the supply of fuel to the burner; In a mostaitic m'etaliserves to'operate an electric switch which may cut olf'the supply of fuel iflerentconstruction shown the ther-.

by stopping a motor.

The 'various features of the invention and-:- novel combination of arts. will be un 'derstoo'd from the ollowing description when read in connection with the accompanying drawings illustrate good, practical forms of the invention.

In the drawings Fig. 1 is a top plan view of an oil burner in position to heat a furnace and provided with the safety device of the present invention.

Fig. 2 is a side elevation of Fig. 1.

Fig. 3 is a front view of the control means of the present invention mounted within its casing. I

Fig. 4 is a sectional view taken on the line 4-4 of Fig. 3.

Fig. 5 is an enlarged sectional view of means for supporting the spark gap terminals.

- Fig. 6 is a perspective view of the mechanism of Fig. 3, the casing being partly broken away.

Fig. 7 is an end view of the spark plug shown mounted in a wall of the furnace.

Fig. 8 is a modification of the invention in which the control means operates an electric switch; and

Fig. 9 is a further modification showing a simpler form of control means for operating an'electric switch.

The present invention may be employed with various types of burner having an electric spark plug to ignite the fuel delivered by the burner, and it may also be employed in various other fields.

In the present case the safety device is shown in Figs. 1 and 2 as applied to an oil burner of the type in which the fuel is fed to the burner by air pressure and the supply of fuel is stopped by relieving the air pressure. The fuel for the burner is contained in a closed tank 10 and is delivered to this tank through a supply pipe 11, the upper end of which is closed by a valve 12 actuated by a float lever 13 pivotally secured to a bracket 14. The lever 13 is actuated by the float 15 to seat the valve and cut off the supply of fuel when the fuel has reached a predetermined height in the tank 10.

Upon the tank 10, in the construction shown, is mounted an electric motor 16 that drives a fan within the fan casing 17, and air is delivered by the fan to the burner tube 18 where it serves to atomize the fuel and promote combustion. A pipe 19 leading from the lower portion of the tank 10 to the burner casing 18 conducts fuel to the burner. This burner is elevated above the normal level of the fuel in the tank 10 and fuel is forced through the pipe 19 to the burner by forcing air into the closed tank 10, the air pressure being conveniently supplied by a pipe 20 leading from the fan casing 17 to the tank, and "the volume of air delivered to the tank is controlled by the valve 21.

The delivery end of the burner tube 18 projects into a furnace through the furnace wall 22 and the burner proper is usually so constructed that its delivery end 23 causes theatomized fuel to be discharged in the flaring manner shown. The construction so far described forms no part of the present invention, but is shown to make clear the application of the present invention to this type of'oil burner.

It is necessary to ignite the fuel when the burner is started, and this may be done by means of a spark plug 24 conveniently mounted in a hole in the furnace wall 22. Electric .current may be supplied to the spark plug by the magneto 25 of well known construction, and t e magneto may be mounted at one side of the motor 16 to be driven by this motor.

The usual means for supplying current from a magneto to a spark plug is to provide one wire leading from the magneto to one terminal of the spark plug and the other terminal of the spark plug is grounded, as is also the magneto, so that when the spark jumps the spark gap of the spark plug the current may return to the magneto through the metal frame.

In the present invention the current supplied to the spark plug 24 serves also to operate the safety device to be described, and both terminals of the spark plug are therefore insulated from the outer metal jacket of the spark plug. To this end the terminals 26 and 27 of the spark plug are each provided with an insulating sleeve 28. The terminals 26 and 27 are preferably supported one above the other in a vertical position as shown so that if oil fromthe burner is deposited on the terminals it will drop from the tip of the upper terminal to the lower terminal and will run down the lower terminal away from its tip. It is desirable that the spark plug 24: be mounted in the Wall 22 so that it may be readily removed and replaced, that it may be easily inspected and cleaned. To this end it is slidably mounted in a hole of the wall 22 and may be held therein by a clip 29 nivoted at 30 to swing to and from the plug holding position. A key 31 may be provided, to insure that the plug be inserted in its proper angular position.

The safety device of Figs. 1 to 6 inclusive serves to control a bleed valve that is opened to relieve-the air pressure in the tank 10 and thus stop the feed of fuel to the burner when the spark plug fails to produce ignition sparksf To this end a casing 32 is provided having a threaded nipple 33 that may be screwed into a wall of the tank 10 so that air may escape from the tank through this nipple. V the nipple 33 is closed by a valve 3 lwhich is shown in the open position in Fig. 3 and in the closed position in Fig. 6, and the ar- The discharge end of is held in t e closed position, but when the spark plugfails to produce an ignition spark the valve 34 is opened to relieve the air pressure in the tank 10 and stop the supply of fuel to the burner.

The means shown for controlling the position of the valve 34 consists of a strip of thermostatic -metal 35 having the curved construction shown, and this strip is firmly secured at one end to a block 36 which may be secured to the inner wall of the casing by screws 37. "The other end of the curved strip is connected to a rocking lever 38 by the link 39. The lever 38 is pivoted at 40 and is provided with a segmental tooth portion 41. The toothed portion 41 meshes with a pinion 42 secured to the shaft 43 which shaft is journaled in the spaced supports 44 and 45, the former support being'secured by. screws 46 to the rear wall of the casing 32 and the support is carried by the sup-.

secured to a block 47 port 44. 7

As the temperature of the thermostatic strip 35 increases the arc of its curvature increases and the end to which the link 39v is connected moves outwardly, thus rocking the lever 38 in a contra-clockwise direction. This turns the shaft 43in a clockwise direction. The valve 34 is secured to an arm 48 mounted upon. the shaft 43 so that as the strip 35 expands it moves the valve to the closed position. The swinging movement imparted to the arm 48 is limited in one direction by the engagement of the valve 34 with the end of the'nipple 33, and may be limited in the oppositedirection by a stop.-

This restricted movement permitted the arm 48 should not act to restrict the movement of the thermostatic strip as the curve of the strip 35 maybe permanently changed if it is not permitted to expand freely. The arm 48 is therefore frictionally secured to the shaft 43, and to this end the shaft 43 is provided with a rigid hub or enlargement 49 upon which the arm 48 is mounted and the arm may have a laterally bent portion 50 that increases the bearing surface between the hub and arm. The arm is rotatably mounted upon the hub 49 and a wire spring 51 rigidly secured to the arm by a screw 52 rests against the hub 49, and this spring frictionally imparts the rotative movement of the hub 49 to the arm 48.

As stated the amount of electric energy commonly supplied to a spark. plug is so small that it will not operate the usual electrical regulating devices, furthermore, due to the pulsating nature of the current employed, it is not well adapted to operate such devices Therefore, in order to provide a safety device that may be controlled by the current delivered to a spark plug, the

'54 to reduce the heating effect.

thermostatic strip 35 is provided with one terminal 53 preferably located near the central portion of the strip, anda second terminal 54 is supported in spaced relation to the terminal 53 to form a spark gap between them. As sparks jump across the'gap they heat the terminals 53 and 54 to a high degree and the terminal 53 heats the thermostatic strip 35 so that it will expand and hold' the valve 34 closed. The terminal 54 preferably is supported near the inner face of the strip 35 so that as the temperature of the terminals increases the strip 35 will move its terminal away from the terminal The terminal 54 may be supported by the threaded bolt 55 having threaded engagement with the bore of the sleeve 56 securedto the casing 32, and the inner end of the bolt 55 is bent, as best shown in Fig. 5 to clear the strip 35. 7

Current is supplied to the lower terminal 27 of the spark plug by a wire 57 leading from the magneto 25, and the upper terminal 26 is connected to the threaded bolt 55 by the wire 58. The casing 32 is grounded, as is also the magneto 25. The current therefore passes from the magneto along the wire 57 to the spark plug 24 and upon jumping from the terminal 27 to the terminal 26 to produce the ignition spark, it passes along the wire 58 to the bolt 55 and terminal 54;

it then jumps across the spark gap to the terminal 53 and then travels back to the magneto through the grounded casing 32 and supporting frame.

As long as the spark plug 24 produces an ignition spark the valve 34 is held in its closed position, and if for any reason the current fails to jump the gap of the spark plug it will fail also to reach the terminal 54. The terminals will then cool off and the thermostatic strip 35 will contract to open the bleed valve 34, whereupon the air pressure in the tank 10 will be reduced and the supply of fuel to the burner will be cutoff. The thermostat strip 3.5 and associated parts are enclosed in the casing 32 to protect the strip from sudden air changes and this casing may be provided with a glass front plate 59.

In some. cases it may be desirable to em ploy the subject matter of the present invention to open and close an electric switch, and means to this end are shown in the modifications of Figs. 8 and 9. In Fig. 8 the thermostatic strip 35 may operate an arm 60 which is frictionally driven by the shaft 43 the same as in Fig. 3, and this arm may have a contact 61 adapted to engage a contact post 62 to ,close a battery circuit.

'The contact 61 may be connected to a post by the Wire 67. The battery circuit just described is provided so that the contacts 61 and 62 will not be subjected to the stronger current of the ordinary electric igniting system. When the arm is moved to close the battery circuit this may excite a solenoid 68 included in the battery circuit and the solenoid may serve to open the switch 69 of the ordinary electric light system. The opening of this switch may stop an electric motor employed to feed fuel to a burner, in which case, should the spark plug used to ignite the fuel in the furnace fail, the electric motor supplying fuel to the furnace would be stopped automatically.

In Fig. 9 a simpler form for controlling an electric switch is shown.- In this view the strip of thermostatic metal 70 is rigidly secured at one end to the base 71. This strip is provided with one terminal 72 of a spark gap similar to the terminal 53 and the other terminal 73 of the spark gap is supported by the base 71 and is connected to the wire 58. The free end of the strip 70 is provided with one contact 74 of an electric switch, and is moved by the thermostatic strip into and out of engagement with the other switch contact 75. The contact 75 is connected to a battery 76 by a wire ,77 and the contact 74 is connectedto this battery by the wire 78, and the battery circuit may control a solenoid 68 the same as in Fig. 8.

What is claimed is: r I

1. In a device of the class described,,in combination, a spark plug, a 'source'of electric current for producing electric sparks between the terminals of the spark plug, a pair of terminals other than those of the spark plu and positioned to form a spark gap, an electric connection between a terminal of the spark plug and a terminal of said spark gap, and means controlled by the current delivered by the spark plug, comprising a piece of thermostatic metal supported to bendunder varying temperatures to actuate a control element and provided with one terminal of said spark gap which is heated by the sparks jumping said gap and causes the metal to bend.

2. In a device of the class. described, in combination, a spark plug, a source of electric current for producing sparks between the terminals of the spark plug, a piece of thermostatic metal provided with one terminal of a spark gap and adapted to be heated by said terminal when sparks jump said gap,'a second terminal of said spark gap electrically connected to one of the terminals of the spark plug to receive the current delivered by the spark plug so that the thermostatic metal is heated by its spark gap terminal as long as the spark plugIfunc-' tions properly. a i o 3. In a device of the class described, in

.spark plug and a terminal of said spark gap arranged so that only the current that has jumped the space between the terminals of the spark plug will cross said spark gap to heat the thermostatic metal.

4. In a. device of the class described, in combination, a fuel igniting spark plug, a source of electric current for producing sparks between the terminals of the spark plug, and means for cutting off the supply of fuel when the spark plug fails to produce a spark, comprising a piece of thermostatic. metal supported to bend under varying temperatures to and from a position to stop the supply of fuel, terminals spaced to form a spark gap and one of the terminals being secured to the thermostatic metal :to heat the metal when sparks jump said gap, and a connection between a terminal of the spark plug and a terminal of the spark gap for heating the thermostatic metal as long as the spark plug functions properly.

5. In a device of the class described, in combination, a pair of electric terminals spaced to form a spark gap,asource of electric current connected to said terminals to produce a series of sparks across said gap, and means for utilizing the terminal heating effect of the sparks crossing said gap to actuate a control element, comprising a control element constructed to be moved 'to and from a closed position, and a piece of thermostatic material for actuating the control element provided with one of said terminals and constructed to be heated sufficiently by said terminal upon sparks jumping said gap to actuate the control element.

6. In a device of the class described, in combination, a pair of terminals spaced to form aspark gap, a source of electric current for producing a series of sparks across said gap, a control element constructed to be moved to and from a closed position, a strip of thermostatic metal for actuating the control element supported to bend-to different degrees with changes in temperature and provided with one terminal of said spark gap which is sufficiently heated by sparks jumping the gap to hold the control element in one position as long as the sparks are produced and in a second position when the sparks fail, and means for supporting the other terminal of the spark gap so that the thermostatic. metal moves to increase the distance between theterminals as the temperature of the thermostatic metal increases.

combination, a spark plug, a source of electric current for producing sparks between the terminals of the spark plug, a control element movable to and from a closedposition, a piece of thermostatic metal for shifting said element with temperature changes, terminals spaced to form a spark gap and one of the. terminals being secured to the thermostatic metal so that as this terminal is heated by sparks jumping the spark gap itwill heat the thermostatic metal to actuate the control element, and an electric connection between a terminal of the spark plug and a terminal of the spark gap for supplying the latter with current only when the spark plug is functioning properly.

8. In a device of the class described, in combination, a pair of terminals spaced to form a spark gap, a source of electric current for producing sparks at frequent in tervals across said gap, a control element constructed to be moved to and from a closed position, a strip of thermostatic metal for actuating the control element supported to bend to different degrees with changes in temperature and provided with one terminal I of said spark gap which is sufficiently heated by sparks jumping the gap to hold the con trol element in one position as long as the sparks are produced and in a second posi tion when the sparks fail.

9. In a device of the class described, in combination, a pair of terminals spaced to form a spark gap between them, a source of electric current for producing sparks between said terminals, a rocking lever movable to and from a closed position, a strip of thermostatic metal supported at one end and having its other end operatively connected to said lever to shift the lever with variations in temperature, and one of said terminals being mounted upon the thermostatic metal so that as this terminal is heated by sparks jumping the spark gap it will heat the thermostatic metal to actuate the lever.

10. In a device of the class described, in combination, a pair of terminals spaced to form' a spark gap between them, a source of electric current for producing sparks between said terminals, a rocking lever movable to and from a. closed position and having a stop; for limiting its path of movement, a strip of thermostatic metal supported at one end, a connection between the other end of the thermostatic strip and the lever to shift the lever with variations in temperature and constructed to yield so that the stop that limits the movement of the lever Wlll not restrict the movement of the thermostatic strip, and one of said terminals being mounted upon the thermostatic strip so that as this terminal is heated by 1 sparks jumping the spark gap it will heat 7. In a device of the class described, in

'form a spark gap and one terminal being secured to the thermostatic metalso that it will heat the metal when this terminal is heated by sparks jumping said gap, and means for conducting current from said spark plug to said spark gap.

12. A safety device for electrically ignited oil burners, comprising in combination, an oil burner having fuel feeding means, a spark plug for igniting the fuel, a source of current for the spark plug, a controller movable to and from position to stop the supply of fuel to the burner, a piece of thermostatic metal for actuating the control ler upon variations of temperature, a pair of terminals spaced to form a spark gap and one terminal being secured to the thermostatic metal so that this-terminal will heat the metal when it is heated by sparks jumping said gap, and a connection between a terminal of the spark plug and a terminal of said gap arranged so that the thermostatic metal will be heated only when ignition sparks are produced by the spark plug.

13. A safety device for electrically ignited oil burners, comprising in combination, an oil burner having fuel feeding means, a spark plug for igniting the fuel, a source of current for the spark plug, a controller movable to and from position to stop the supply of fuel to the burner, a piece of thermostatic metal for actuating the controller upon variations of temperature, a pair of terminals spaced to form a spark gap and one of which is secured to the thermostatic metal so that it will heat the metal when it is heated by sparks jumping said gap, and means connecting the terminals of the spark plug to the terminals of the spark .of thermostatic metal for actuating the con- ..troller upon variations of temperature, a

pair of terminals spaced to form a spark gap and one of which is secured to the thermostatic metal so that it Will heat the metal when it is heated by sparks jumping said gap, and a connection between a terminal of the spark plug and a terminal of said spark gap.

15. A safety device for electrically ignited oil burners, comprising, in combination, an oil burner, means employing air pressure to feed fuel to the burner, a controller operable to relieve said air pressure to thereby stop the-supply of fuel to the burner, electrical means for igniting the fuel, a piece of thermostatic metal for actuating the controller upon variations of temperature, a pair of terminals spaced to form a spark gap and one terminal being secured to the thermostatic metal so that it will heat the metal when itis heated by sparks jumping said gap, and means for connecting said terminals in the circuit with the electrical igniting means.

16. A safety device for electrically ignited oil burners, comprising in combination, an oil burner having an air pressure chamber and means for forcing air into the chamber to feed oil to the burner, a bleed-valve for reducing the air pressure in said chamber to stop the supply of fuel to the burner, a spark plug for igniting the fuel, a source of current for the spark plug, a piece of thermostatic meta-l operable with changes in temperature to open and close said bleed-valve, a pair of terminals spaced to form a spark gap and having one terminal secured to the thermostatic metal so that it will heat the metal when the termi nal is heated by sparks jumping said gap, and means connecting a terminal of the spark plug with a terminal of the spark gap.

17. A safety device for electrically ignited oil burners, comprising in combination, ,an oil burner having .fuel feeding means, a controller movable to and from position to stop the supply of fuel to the burner, a spark plug for igniting the fuel, a source of current for the spark plug, a strip of thermostatic metal for actuating the controller upon variations of temperature, a friction connection between the thermostatic strip and controller for permitting the movement of the controller to be arrested without arresting the bending movement of said strip, a pair of terminals spaced-toform a spark gap and one of which is secured to the thermostatic strip so that it will heat the strip when the terminal is heated by sparks jumpingsaid gap, and means connecting a terminal of the spark plug with a terminal of said gap.

18. A safety device for electrically ignited oil burners, comprising in combination, an

oil burner having fuel feeding means, a

-minal of said gap so that as the strip expands under an increasing temperature it will increase the distance between the terminals, and means connecting a terminal of the spark plug with a terminal of said gap. 19. In a device of the class described, in combination, a spark plug, a magneto connected to the spark plug for producing electric sparks between the terminals of the spark plug, a pair of terminals other than those of the spark plug and positioned to forma spark gap, a piece of thermostatic material supported to bend under varying temperatures to actuate a control element and provided with one terminal of said spark gap which is heated by the sparks 'umping said gap and causes the metal to end, and means for connecting the terminals of the spark gap in the circuit including the magneto and spark plug.

In testimony whereof, I have'signed my name to this specification.

' MILTON A. FESLER. 

